Pact of the Infinite Archive

Beyond the mapped reaches of the planes lies an archive without known boundary. Its halls extend through forgotten demiplanes, abandoned divine realms, lost moments in history, and places that exist only within memory. Its shelves contain books never written, biographies of people who were erased from existence, maps of worlds that no longer survive, and sealed volumes whose contents could unravel civilizations.

This place is known by many names: the Infinite Archive, the Library Beyond Hours, the House of Unfinished Histories, the Index of Worlds, and the Last Repository. Its keeper is known simply as the Librarian.

No reliable account agrees on the Librarian’s nature. It may be an ancient celestial scribe, a deity of knowledge stripped of worship, a collective intelligence formed from every preserved text, an immortal construct created before the current gods, or the sentient will of the Archive itself. Some visitors describe a robed scholar with a face hidden behind parchment. Others encounter a many-eyed serpent coiled around an endless index, a chorus of whispering books, or an empty chair before which pages turn without assistance.

Warlocks of the Infinite Archive are appointed as collectors, curators, retrieval agents, field archivists, and custodians of dangerous knowledge. Their patron grants them access to a supernatural codex connected to the Archive’s catalogues. In return, they recover lost texts, document previously unknown creatures, preserve endangered histories, and acquire secrets their patron considers worthy of inclusion.

The Librarian’s pursuit of knowledge is not necessarily benevolent. It values preservation, accuracy, and acquisition, but it may not distinguish between knowledge that enlightens and knowledge that destroys. A civilization’s extinction may be regrettable, yet perfectly acceptable if its complete history has already been catalogued.

A Warlock serving the Infinite Archive must therefore confront a difficult question: is knowledge valuable because it serves life, or is life merely a temporary source of information?

Origins in Aetheris

References to the Infinite Archive appear throughout Aetheris, though most scholars dismiss them as different myths describing unrelated repositories.

The oldest credible references occur in surviving records from before the Shadowfell incursions. Several describe doors appearing in ruined academies, sealed tombs, or abandoned temples. Those who entered sometimes returned years later without having aged, carrying books written in languages that had not yet been invented.

The Archive’s interest in Aetheris appears to have intensified after the Comet of Suthakhet, the incursions from the Feywild and Shadowfell, and the disturbances caused by the Old Ones. Each event generated new forms of magic, altered historical records, and destroyed irreplaceable knowledge.

Known pact traditions appear throughout the world:

• In the Concord of Veltrion, Archive Warlocks serve as occult researchers, investigators, and custodians of restricted collections.
• In the March of Draeven, authorized pact-bearers help identify dangerous relics, magical forgeries, and altered state records.
• In the Freeholds of Rhonadral, independent archivists recover lost journals, ship logs, ruin maps, and testimony from vanished settlements.
• In the Helbrann League, Warlocks preserve cantonal histories, engineering records, and accounts hidden during past invasions.
• In the Evershade Sovereignty, they investigate memories altered by Fey magic and histories rewritten through glamour.
• In the Skyborne Dominion, ambitious arcanists seek the Archive’s forbidden theories concerning planar engineering and the Old Ones.
• In Sahariad, Archive agents search beneath the desert for records predating the Comet of Suthakhet.
• In Drakthar, clandestine archivists preserve cultures and testimonies targeted for destruction by the Obsidian Hegemony.
• In the Dominion of Xathrin, possession of an Archive Codex is closely controlled, as the patron’s records may expose soul contracts and erased atrocities.

A pact may begin when a mortal:

• Discovers a book that records their actions before they perform them.
• Reads a name that has been erased from every other source.
• Becomes trapped in an impossible library.
• Saves a manuscript from deliberate destruction.
• Trades a cherished memory for forbidden knowledge.
• Agrees to recover a missing volume.
• Encounters the Librarian while near death.
• Writes a question in an empty book and receives an answer.
• Opens a door that should lead nowhere and finds endless shelves beyond it.

The Librarian rarely asks whether a prospective servant is morally good. Curiosity, discipline, memory, adaptability, and willingness to retrieve dangerous information are of greater importance.

Philosophy and Doctrine

Warlocks of the Infinite Archive do not share a single moral code, but the Librarian’s instructions repeatedly emphasize several principles.

Knowledge Must Be Preserved

A destroyed record can never be examined, corrected, challenged, or understood. Even dangerous knowledge should be preserved somewhere, though it need not remain accessible.

Accuracy Is Sacred

An incomplete truth is preferable to a deliberate lie. An archivist must distinguish observation from inference and certainty from speculation.

Context Gives Meaning

A fact without context can mislead more effectively than a falsehood. Events, names, artifacts, and spells must be recorded alongside their origins and consequences.

Nothing Is Beneath Documentation

The lives of farmers, soldiers, prisoners, artisans, and forgotten communities may reveal more than the proclamations of rulers.

Access Is Not Entitlement

Knowledge may be preserved without being shared. Some truths must be sealed until those seeking them can survive their consequences.

Memory Is Evidence, Not Perfection

Memory can be altered, misunderstood, or corrupted. It remains valuable, but it must be compared against other records.

Destruction Requires Judgment

Some knowledge is actively predatory. A sentient curse, Old One formula, or infectious revelation may be too dangerous even for conventional preservation. Archivists debate whether such information should be sealed, transformed, or erased completely.

The central tension of the pact lies between preservation and responsibility. The Librarian may command a Warlock to save a text that should never be read, record an atrocity rather than prevent it, or allow a dying culture to vanish after its history has been secured.

Visual Identity

Warlocks of the Infinite Archive often resemble traveling scholars, occult investigators, formal curators, or armored custodians.

Common garments and equipment include:

• Long coats with reinforced pockets for notebooks and tools.
• Layered robes embroidered with script, indexes, or geometric catalog marks.
• Dark leather satchels containing scroll cases and specimen containers.
• Spectacles, monocles, lenses, or masks etched with arcane formulae.
• Gloves designed for handling dangerous texts.
• Bookmark ribbons worn as sashes or cords.
• Keys, seals, clasps, and numbered metal tags.
• Ink-stained cuffs.
• Protective collars and mantles resembling folded pages.
• Armor engraved with excerpts from lost histories.

Typical colors include ivory, parchment, black, deep blue, burgundy, bronze, dark green, silver, and muted violet.

Their magic may manifest as:

• Spectral pages turning in empty air.
• Glowing script circling a creature.
• Ink spreading across invisible surfaces.
• Books opening behind the Warlock.
• Shelves appearing momentarily in darkness.
• Luminous index cards or catalog slips.
• Quills writing without hands.
• Eyes formed from letters.
• Geometric diagrams unfolding around spells.
• Whispered citations spoken by unseen voices.
• Chains and seals closing around forbidden information.
• A vast library appearing briefly behind an open doorway.

The Warlock’s Codex reflects their relationship with the patron. It may appear as a heavy chained tome, a collection of floating tablets, an endless scroll, a metal-bound field journal, a deck of inscribed cards, or a book whose pages are made from translucent light.

Role in Aetheris

Battlefield Role

The Pact of the Infinite Archive functions as a controller, tactical support caster, and magical investigator. It identifies enemy defenses, improves critical rolls, disrupts spellcasters, and temporarily accesses specialized magical knowledge.

Social Role

Archive Warlocks commonly serve as historians, translators, forensic scholars, occult investigators, ruin specialists, diplomatic researchers, codebreakers, and custodians of restricted collections.

Political Role

Governments value their ability to recover suppressed records and identify magical deception, but fear their connection to a repository beyond national control. An Archive Warlock may possess evidence capable of undermining dynasties, treaties, or official histories.

Religious Role

The Librarian may be interpreted as a god, celestial agent, primordial intelligence, or extraplanar institution. Some Warlocks worship it. Others consider their relationship academic, contractual, or custodial.

Adventuring Role

Within an adventuring company, the subclass provides identification, translation, investigation, enemy analysis, magical countermeasures, and flexible problem-solving.

Subclass Integration

Major Polities

Concord of Veltrion

The Concord permits registered Archive Warlocks to work within universities and investigative bodies. Access to restricted historical collections remains tightly controlled.

March of Draeven

Draeven authorities employ selected pact-bearers to authenticate official records, investigate magical tampering, and catalogue dangerous artifacts. Unauthorized access to military archives is treated as espionage.

Freeholds of Rhonadral

Independent archivists frequently work as explorers, private researchers, mapmakers, and investigators. Their decentralization makes them difficult for the Librarian—or any government—to supervise.

Helbrann League

Archive Warlocks assist cantons in preserving technical knowledge, treaties, bloodlines, and local histories. Many Helbranni insist that copies of all recovered records remain under community control.

Evershade Sovereignty

The pact is especially useful in identifying memories and histories altered through Fey influence. Evershade scholars nevertheless distrust the Librarian’s habit of collecting originals rather than copies.

Skyborne Dominion

Dominion arcanists aggressively seek access to the Infinite Archive. Several have entered pacts specifically to retrieve theories relating to planar travel, divine architecture, and the Old Ones.

Dominion of Xathrin

Xathrin permits only closely supervised Archive Warlocks. Unsanctioned Codices are confiscated because they may contain evidence of erased citizens, illegal soul transactions, or contradictory religious records.

Obsidian Hegemony

The Hegemony attempts to capture Archive Warlocks and force access to their Codices. Clandestine pact-bearers preserve the names and histories of communities targeted for eradication.

Organizations and Orders

Likely connections include:

• Universities and arcane colleges.
• Monastic scriptoria.
• Antiquarian guilds.
• Cartographers.
• Intelligence services.
• Investigative offices.
• Mortuary archives.
• Museums.
• Ruin-exploration companies.
• Blood Hunter orders studying supernatural creatures.
• Religious libraries.
• Secret societies preserving censored histories.
• Guilds of translators and scribes.
• The Eightfold Ledger, which seeks to purchase Archive information.
• The Meridian Consortium, which covets maps and records of hidden populations.

Religious and Philosophical Movements

The pact attracts scholars who regard knowledge as sacred, but it also produces conflicts between preservationists, censors, reformers, and those who believe dangerous knowledge should be destroyed.

Rival Factions and Enemies

Frequent enemies include:

• The Eightfold Ledger.
• The Meridian Consortium.
• The Dominion of Xathrin.
• The Obsidian Hegemony.
• Censors and historical revisionists.
• Cults that erase names or memories.
• Fey beings that alter personal history.
• Old One cults spreading infectious knowledge.
• Sentient grimoires.
• Rival collectors.
• Liches protecting private archives.
• Creatures that consume memory.
• Institutions that destroy evidence to preserve authority.

Expanded Spell List

The Infinite Archive adds the following spells to the Warlock spell list for you.

Spell Level	Spells
1st	Comprehend Languages, Identify
2nd	Augury, Detect Thoughts
3rd	Clairvoyance, Counterspell
4th	Arcane Eye, Divination
5th	Legend Lore, Wall of Force

These spells count as Warlock spells for you.

When you cast a spell from this list that requires a material component with a listed gold cost, you must still provide that component unless one of your subclass features specifically states otherwise.

Optional Eldritch Invocations

These invocations are available to Warlocks who have chosen the Pact of the Infinite Archive.

Index of Hidden Things

Prerequisite: Pact of the Infinite Archive

While holding your Codex, you can cast Detect Magic without expending a spell slot.

Once you cast it in this way, you cannot do so again until you finish a short or long rest.

When you examine a magical aura while the spell is active, you also learn whether the magic is concealing, altering, recording, or erasing information.

Perfect Citation

Prerequisite: Pact of the Infinite Archive, 5th level

When you make an Arcana, History, Investigation, Nature, or Religion check and roll a 9 or lower on the d20, you can treat the roll as a 10.

You must be holding your Codex and cannot use this invocation while incapacitated.

Redacted Presence

Prerequisite: Pact of the Infinite Archive, 5th level

You can cast Nondetection on yourself without expending a spell slot or material components.

Once you cast it in this way, you cannot do so again until you finish a long rest.

While the spell is active, magical records created about you show your identity as obscured, redacted, or unavailable.

Footnote of Doubt

Prerequisite: Pact of the Infinite Archive, 5th level

When a creature affected by Index the Subject makes an attack roll or ability check, you can use your reaction to subtract your Archive Die from the roll.

You may use this invocation after the d20 is rolled but before the outcome is declared.

You can use Footnote of Doubt a number of times equal to your proficiency bonus, regaining all expended uses when you finish a long rest.

Catalogue of Monsters

Prerequisite: Pact of the Infinite Archive, 7th level

When you finish a short or long rest, choose one creature type other than humanoid.

Until you choose another type with this invocation, you have advantage on Intelligence checks made to recall information about creatures of that type.

The first time during each turn that you damage an Indexed creature of the chosen type, it takes additional psychic damage equal to your Charisma modifier.

Door Between Shelves

Prerequisite: Pact of the Infinite Archive, 9th level

You can cast Dimension Door once without expending a spell slot.

When cast through this invocation, you and any accompanying creature pass through a brief corridor lined with impossible bookshelves.

You regain the ability to cast it in this way when you finish a long rest.

Familiar of the Stacks

Prerequisite: Pact of the Infinite Archive, Pact of the Chain

Your familiar can take the form of a spectral scribe, paper bird, ink serpent, or animated book using the statistics of an owl, raven, or imp as appropriate.

The familiar gains proficiency in Arcana, History, Investigation, Nature, and Religion, using your proficiency bonus and its own ability modifiers.

While it is within 100 feet, it can assist you when you Consult the Catalogue even if it is not adjacent to you.

Blade of the Annotated Foe

Prerequisite: Pact of the Infinite Archive, Pact of the Blade, 5th level

When you hit a creature affected by Index the Subject with your pact weapon, you can change the attack’s damage type to force or psychic.

Once per turn, when you hit an Indexed creature, you can learn one of the following:

• Whether it is above or below half its hit point maximum.
• Whether it is concentrating.
• Whether it can currently take reactions.
• Whether it possesses Legendary Resistance.

Book Within the Book

Prerequisite: Pact of the Infinite Archive, Pact of the Tome

Your Book of Shadows and Codex of Secrets become linked volumes.

You can copy ritual spells into your Book of Shadows in half the normal time.

When you complete a ritual from the book, you can ask the Codex for one minor contextual fact related to the spell’s subject. The information must be something that could reasonably be learned through research rather than prophecy.

Talisman of the Corrected Error

Prerequisite: Pact of the Infinite Archive, Pact of the Talisman

When the wearer of your talisman fails an Intelligence, Wisdom, or Charisma ability check, it can roll your Archive Die and add the result to the check.

Once the talisman grants this benefit, it cannot do so again until you finish a short or long rest.

Spellbreaker’s Appendix

Prerequisite: Pact of the Infinite Archive, 9th level

When you successfully interrupt or dispel a spell, choose one creature you can see within 30 feet of the spell’s caster.

That creature gains temporary hit points equal to your Warlock level.

Alternatively, you may cause the caster to take psychic damage equal to your Warlock level.

You can use this invocation once per short or long rest.

Playing This Subclass

Intended Playstyle

The Pact of the Infinite Archive is designed for players who enjoy investigation, preparation, tactical analysis, and flexible magical utility.

At 3rd level, Codex of Secrets establishes the subclass’s scholarly identity. It provides useful proficiencies, translation, controlled identification, and a persistent record of discovered information.

Index the Subject allows the Warlock to select an important creature and determine how best to study it. The chosen Index can improve damage, accuracy, defense, or spell effectiveness, but each field remains narrow enough to reward deliberate selection.

At 6th level, Archival Recall supports important checks and saves without granting unrestricted advantage. Expose the Omission allows the Warlock to capitalize on enemy mistakes and assist the whole party.

At 10th level, Warden of the Archive protects the Warlock’s mind and the information of nearby allies. The Ethereal Archivist creates a mobile area that disrupts concentration, protects against illusions, and allows unusual cantrip positioning.

At 14th level, Tome of Infinite Mysteries transforms the Warlock into a temporary master of analysis. It grants truesight, rotating fields of expertise, multiple simultaneous Indexes, one borrowed Wizard spell, and protection against losing concentration.

Strengths

• Excellent knowledge and investigation utility.
• Reliable translation and identification.
• Flexible single-target analysis.
• Strong support for ability checks and saving throws.
• Useful anti-spellcaster tools.
• Resistance to psychic damage.
• Strong protection against memory alteration and mind reading.
• Truesight during the capstone.
• Access to one flexible borrowed spell.
• Extensive roleplaying and exploration utility.

Weaknesses

• Limited direct defensive improvements before 10th level.
• Several features compete for the reaction.
• Lower raw damage than offensive Warlock patrons.
• Index the Subject affects only one creature before the capstone.
• Strong utility can depend on campaign subject matter.
• Many abilities require the Codex to be available.
• The patron may demand acquisition of dangerous knowledge.
• Knowledge obtained from the Archive may be incomplete or politically hazardous.
• The subclass has limited healing.
• Creatures with strong mental defenses may resist its more subtle tools.

Tactical Identity

A typical encounter might proceed as follows:

1. Determine which enemy presents the greatest threat.
2. Apply the Index most useful against that creature.
3. Position the Ethereal Archivist near enemy spellcasters or vulnerable allies.
4. Use Warlock spells to trigger Expose the Omission.
5. Reserve Archival Recall for a critical saving throw or ability check.
6. Use Custodian’s Interdiction against possession, memory alteration, or invasive divination.
7. Invoke Tome of Infinite Mysteries during a decisive encounter.
8. Select a new field of Infinite Cross-Reference each round according to the situation.

Roleplaying This Subclass

Warlocks of the Infinite Archive are often inquisitive, observant, and unable to ignore unanswered questions.

Some are patient scholars. Others are obsessive collectors who treat every event as research material.

Common traits include:

• Taking notes during inappropriate moments.
• Asking for exact names, dates, and sources.
• Correcting inaccurate stories.
• Preserving even dangerous books.
• Distrusting undocumented claims.
• Treating personal memories as evidence.
• Keeping several classification systems.
• Becoming distracted by unusual inscriptions.
• Refusing to destroy unique records.
• Recording the names of ordinary people omitted from official histories.
• Speaking in citations or references.
• Leaving blank pages for future corrections.

Narrative Tensions

Preservation or Safety

The Warlock may discover knowledge too dangerous to retain.

Truth or Compassion

Accurate information can destroy reputations, faiths, relationships, and nations.

Observer or Participant

The Librarian may instruct the Warlock to document an event rather than interfere.

Collection or Theft

Recovering knowledge may require taking sacred or culturally important objects from their rightful keepers.

Memory or Identity

Repeatedly sealing, borrowing, and cataloguing memories may change how the Warlock understands their own life.

Patron or Institution

The Librarian may be a person, a role, or merely the visible interface of the Archive itself.

Faction and Organization Connections

Likely Allies

• Universities.
• Libraries.
• Historical societies.
• Arcane colleges.
• Cartographers.
• Investigators.
• Monastic scribes.
• Museums.
• Ruin explorers.
• Religious archivists.
• Blood Hunters researching monsters.
• Communities preserving endangered histories.
• Rebel groups documenting atrocities.
• Scholars studying the Old Ones.

Likely Patrons or Intermediaries

• The Librarian.
• A masked Curator.
• A sentient catalogue.
• A spectral scribe.
• An animated volume.
• A council of archived minds.
• A former Warlock preserved as an index.
• An entity claiming to be the Library itself.

Common Enemies

• The Eightfold Ledger.
• The Meridian Consortium.
• The Dominion of Xathrin.
• The Obsidian Hegemony.
• Censors.
• Historical revisionists.
• Memory thieves.
• Fey manipulators of identity.
• Sentient curses.
• Liches guarding private knowledge.
• Cults of the Old Ones.
• Organizations that destroy evidence.
• Rival collectors who refuse to distinguish preservation from ownership.

Adventure Hooks

The Book That Is Still Being Written

A newly discovered book accurately records every major event in the party’s journey, including several events that have not yet occurred.

The Missing Century

Every historical record covering the same hundred-year period has been removed from Aetheris. The Archive contains the only known surviving catalogue entry, but the volume itself is missing.

The Curator’s Defection

A powerful Archivist has fled the Infinite Archive carrying a collection of sealed Old One texts. The Librarian demands their recovery intact.

The Village Without Names

An entire settlement has lost the ability to remember personal names. The stolen names have appeared as a new volume in the Archive.

The Last Copy

Two nations are preparing for war over the only surviving copy of a foundational religious text. The Librarian orders the Warlock to acquire the original.

The False Librarian

Another entity has begun offering pacts in the Librarian’s name. Its Warlocks collect living memories rather than books.

Notable NPCs

Curator Elian Voss

Species: Human
Homeland: Concord of Veltrion
Role: Restricted-archive investigator

Elian specializes in identifying forged histories and magically altered records. He carries a Codex formed from hundreds of loose pages orbiting a black metal spine.

He believes the Infinite Archive is fundamentally benevolent, though he has never answered why it preserves instructions for atrocities alongside records of their victims.

Mara Kest d’Rhyd

Species: Arden Rhyd
Homeland: Drakthar
Role: Clandestine historian and resistance archivist

Mara records the names, traditions, and testimonies of communities threatened by the Obsidian Hegemony. Her Codex resembles a battered military journal that cannot be burned.

She refuses to surrender original records to the Infinite Archive unless a copy remains with the people whose history they contain.

Talaris the Redacted

Species: Fallen
Homeland: Unknown
Role: Retrieval agent for forbidden volumes

Talaris has sealed so many memories that large portions of their identity are inaccessible even to them. Their face appears blurred in magical recordings, and their original name has been removed from every known document.

They claim this was necessary to conceal a fact capable of awakening an Old One.

Balance Notes

Intended Role

Primary: Controller and tactical support
Secondary: Investigator and anti-caster

Damage Profile

The subclass receives only moderate damage improvements.

Anatomical Index adds proficiency bonus damage once per turn against one target. Expose the Omission can add limited damage or improve a single attack. The capstone can improve one attack each round through Battle Doctrine.

The subclass does not grant a universal increase to Eldritch Blast, and its strongest abilities emphasize knowledge and control rather than raw damage.

Survivability

The subclass gains psychic resistance and mental protections at 10th level.

Archival Recall can improve saving throws, while Corrective Citation can mitigate damage from a failed save.

The Ethereal Archivist provides specialized protection against illusions and magical concentration but does not grant broad advantage against all spells and magical effects.

Utility

The subclass offers substantial utility through:

• Translation.
• Identification.
• Knowledge proficiencies.
• Charisma-based scholarly checks.
• Information storage.
• Enemy analysis.
• Protection against memory alteration.
• Mind-reading resistance.
• Truesight.
• Limited access to a borrowed spell.
• Specialized invocations.

This utility is broad but depends upon the Warlock’s choices, resources, and actual discoveries.

Resource Economy

The subclass uses:

• Proficiency-bonus uses of Index the Subject.
• Charisma-modifier uses of Consult the Catalogue.
• Proficiency-bonus uses of Archival Recall.
• Charisma-modifier uses of Expose the Omission.
• Proficiency-bonus uses of Custodian’s Interdiction.
• One use of Ethereal Archivist per long rest, with one Pact-slot recovery.
• One use of Tome of Infinite Mysteries per long rest.
• One additional capstone use through a 5th-level Pact Magic slot and exhaustion.

Several abilities compete for the Warlock’s reaction, requiring meaningful tactical choices.

Comparison to Similar Subclasses

Compared with the Great Old One patron, the Infinite Archive offers:

• Less direct telepathy.
• Stronger scholarly utility.
• Greater protection against memory manipulation.
• More structured enemy analysis.
• Less broad psychic offense.

Compared with the Genie patron, it offers:

• Less elemental damage.
• Less personal sanctuary.
• More investigation and anti-caster utility.
• Greater access to contextual knowledge.

Compared with the Hexblade, it offers:

• Much lower weapon effectiveness.
• Better skill and research utility.
• Stronger anti-magic support.
• Less armor and direct durability.

Compared with the Celestial patron, it offers:

• Little direct healing.
• Better knowledge support.
• Stronger mental defenses.
• More flexible enemy analysis.

Potential Risks

The original ability to grant advantage on all attacks against one creature was replaced with narrower Index options and a single exposed weakness. This prevents the subclass from overwhelming high-priority enemies through party-wide advantage.

The ability to use any cantrip was replaced with the ability to cast a known Warlock cantrip through the Archivist’s space. This preserves unusual positioning without creating unrestricted access to every class list.

The capstone no longer allows concentration on two spells. Double concentration can create disproportionately powerful combinations and undermines a major balancing rule for spellcasters.

Borrowed Formula is limited to one Wizard spell of 5th level or lower during the capstone and does not bypass expensive or consumed material components.

The Librarian’s answers should be truthful but not omniscient. Artifacts, deities, Old Ones, and comparable powers may conceal information from the Archive.

Summary

The Pact of the Infinite Archive transforms the Warlock into a supernatural scholar, field archivist, and custodian of dangerous knowledge.

Its defining feature is the Codex of Secrets, a permanent connection to an impossible planar library. Through the Codex, the Warlock translates texts, identifies magic, preserves discoveries, and consults knowledge beyond their personal education.

Index the Subject allows the Warlock to analyze one important creature and select the tactical field most useful against it. Archival Recall protects critical rolls, while Expose the Omission converts enemy errors into openings for the party. At higher levels, the Warlock protects memories, manifests an Ethereal Archivist, and briefly accesses the Tome of Infinite Mysteries.

The subclass is intended for players who enjoy investigation, tactical flexibility, arcane scholarship, hidden histories, and the moral uncertainty of serving a patron that may value the preservation of knowledge more than the survival of those who create it.

“Do not fear that you will be forgotten. Fear that the Archive will remember you perfectly.”

Tome of Infinite Mysteries

The Librarian opens a restricted portion of the Archive to you, surrounding your mind with impossible catalogues and unrealized possibilities.

As an action, you enter a state of Perfect Recall for 1 minute.

The effect ends early if you are incapacitated or dismiss it as a bonus action.

While Perfect Recall lasts, you gain the following benefits.

Unclouded Perception

You gain truesight to a range of 60 feet.

You can see into the Ethereal Plane within this range.

You automatically recognize illusions as magical, though you do not necessarily perceive the truth they conceal unless your truesight reveals it.

Infinite Cross-Reference

At the beginning of each of your turns, choose one field of knowledge from the following list:

• Arcane Formulae.
• Battle Doctrine.
• Creature Lore.
• Planar Geography.
• Protective Precedent.
• Social Histories.

You gain the associated benefit until the beginning of your next turn.

Arcane Formulae

You have advantage on Constitution saving throws made to maintain concentration.

When you succeed on such a saving throw, you can move up to 10 feet without provoking opportunity attacks.

Battle Doctrine

Once during the turn, when you make an attack roll, you can roll your Archive Die and add it to the attack.

If the attack hits an Indexed creature, add the Archive Die to one damage roll as well.

Creature Lore

You immediately learn whether each creature you can see within 60 feet possesses any damage vulnerabilities, resistances, or immunities.

You learn the damage types, but not the source of those traits.

Planar Geography

You cannot be teleported or moved to another plane against your will.

Your movement ignores difficult terrain, and you can move through the spaces of other creatures as difficult terrain.

Protective Precedent

You gain advantage on saving throws against spells and magical effects.

When you succeed on such a saving throw, you gain temporary hit points equal to your Charisma modifier plus your Archive Die.

Social Histories

You understand the literal meaning of every spoken language you hear.

You have advantage on Insight and Persuasion checks.

Magic cannot determine whether you are deliberately withholding information.

Living Index

You can maintain Index the Subject on up to three creatures at the same time.

When you apply an Index during Perfect Recall, you may choose a different field of study for each creature.

Applying Index the Subject during this feature does not expend a use, but a creature must still be within range and visible to you.

All free Indexes end when Perfect Recall ends.

Borrowed Formula

Once during Perfect Recall, you can cast one spell of 5th level or lower from the Wizard spell list.

The spell must have a casting time of 1 action, bonus action, or reaction.

It counts as a Warlock spell for you, uses your Warlock spellcasting ability, and requires no material components unless they have a listed gold cost or are consumed.

You cast the spell at 5th level without expending a spell slot.

Once you use Borrowed Formula, you cannot use it again during the same activation.

Unbroken Concentration

When you fail a Constitution saving throw to maintain concentration, you can choose to succeed instead.

Once you use this benefit, you cannot use it again during that activation of Perfect Recall.

This feature does not permit you to concentrate on more than one spell at a time.

Consult the Forbidden Shelves

Once during the duration, you can ask the Librarian one question as a bonus action.

The question must concern:

• A creature you can see.
• An object you are touching.
• A place visible to you.
• A spell or magical effect active within 60 feet.
• An event directly connected to your current surroundings.

The Game Master provides a truthful answer of no more than twenty-five words based on information the Librarian could reasonably possess.

The answer may be cryptic if the knowledge is protected by a deity, an Old One, an Artifact, or magic of comparable power.

Once you use Tome of Infinite Mysteries, you cannot use it again until you finish a long rest.

You may use it again before finishing a long rest by expending one Pact Magic spell slot of 5th level and gaining one level of exhaustion when the effect ends.

Once you invoke it through this sacrifice, you cannot do so again until you finish a long rest.

Action Type: Action
Uses: Once per long rest; one additional use through a 5th-level Pact Magic slot and exhaustion
Duration: 1 minute
Scaling: Archive Die, Charisma modifier, and Warlock spellcasting

Concentration Limitation

Tome of Infinite Mysteries does not permit concentration on two spells. Instead, it improves concentration resilience and provides one automatic success. This preserves the theme of advanced magical cognition without bypassing one of the game’s principal spellcasting limits.

Manifestations of the Infinite Archive

When your patron’s power manifests, roll or choose from the following table.

d8	Manifestation	Appearance
1	The Turning Pages	Hundreds of translucent pages circle you before returning to an unseen book.
2	The Open Stacks	Endless shelves appear briefly behind you, stretching into darkness.
3	The Watching Index	A luminous eye composed of letters opens above your Codex.
4	The Silent Scribe	A hooded spectral figure records every word spoken nearby.
5	The Falling Letters	Glowing characters descend like snow and vanish before touching the ground.
6	The Locked Volume	A massive chained book appears behind you and opens to a sealed page.
7	The Library Door	A doorway forms in empty space, revealing distant halls filled with floating lights.
8	The Final Citation	An unseen voice recites a title, author, and date in a language everyone understands.

Spellcasting

The Infinite Archive adds the following spells to the Warlock spell list for you.

Spell Level	Spells
1st	Comprehend Languages, Identify
2nd	Augury, Detect Thoughts
3rd	Clairvoyance, Counterspell
4th	Arcane Eye, Divination
5th	Legend Lore, Wall of Force

These spells count as Warlock spells for you.

When you cast a spell from this list that requires a material component with a listed gold cost, you must still provide that component unless one of your subclass features specifically states otherwise.

Codex of Secrets

The Librarian grants you a supernatural volume connected to the Infinite Archive.

As a bonus action, you can summon the Codex into one of your empty hands. It remains until you dismiss it as a bonus action, become incapacitated, or summon it again.

The Codex cannot be permanently destroyed. If damaged or lost, it disappears and can be summoned again.

It may take the form of a book, scroll, tablet, deck of index cards, ring of inscribed metal plates, or another portable repository.

The Codex can be used as a spellcasting focus for your Warlock spells.

While holding it, you gain the following benefits.

Archive Training

You gain proficiency in Arcana.

Choose History, Investigation, Nature, or Religion. You also gain proficiency in the chosen skill.

If you are already proficient in either skill when you gain this feature, choose another skill from the list for that proficiency.

Whenever you make an Intelligence check using a skill granted by this feature, you can use your Charisma modifier in place of your Intelligence modifier.

Reader of All Scripts

You can identify the language in which visible writing is composed, even if you cannot understand it.

You can cast Comprehend Languages as a ritual without expending a spell slot or material components.

Catalogued Identification

You can cast Identify as a ritual without expending a spell slot.

When you do, the Codex replaces the spell’s ordinary material component, but only for an object you hold throughout the ritual.

Once you use the Codex to replace the costly component of Identify, you cannot do so again until you finish a short or long rest. You may still cast the spell normally if you provide its material component.

Marginal Annotation

When you successfully identify a spell, magical effect, creature, object, or written work, you can cause a summary to appear within the Codex.

The summary records only information you actually learned. It cannot generate facts you did not discover.

You can always find information you personally recorded in the Codex unless the relevant page has been suppressed by powerful magic.

Action Type: Bonus action to summon; passive; ritual casting
Uses: At will, except component-free Identify once per short or long rest
Duration: Until dismissed
Scaling: None

Archive Training - History

Choose History, Investigation, Nature, or Religion. You also gain proficiency in the chosen skill.

If you are already proficient in either skill when you gain this feature, choose another skill from the list for that proficiency.

Whenever you make an Intelligence check using a skill granted by this feature, you can use your Charisma modifier in place of your Intelligence modifier.

Archive Training - Investigation

Choose History, Investigation, Nature, or Religion. You also gain proficiency in the chosen skill.

If you are already proficient in either skill when you gain this feature, choose another skill from the list for that proficiency.

Whenever you make an Intelligence check using a skill granted by this feature, you can use your Charisma modifier in place of your Intelligence modifier.

Archive Training - Nature

Choose History, Investigation, Nature, or Religion. You also gain proficiency in the chosen skill.

If you are already proficient in either skill when you gain this feature, choose another skill from the list for that proficiency.

Whenever you make an Intelligence check using a skill granted by this feature, you can use your Charisma modifier in place of your Intelligence modifier.

Archive Training - Religion

Choose History, Investigation, Nature, or Religion. You also gain proficiency in the chosen skill.

If you are already proficient in either skill when you gain this feature, choose another skill from the list for that proficiency.

Whenever you make an Intelligence check using a skill granted by this feature, you can use your Charisma modifier in place of your Intelligence modifier.

Index the Subject

You can open a supernatural entry on a creature and record its actions, defenses, and weaknesses.

As a bonus action, choose one creature you can see within 60 feet. The creature becomes Indexed for 1 minute.

The Index ends early if:

• You are incapacitated.
• You use this feature against another creature.
• The target moves to another plane.
• You dismiss the Index as a bonus action.

When you Index a creature, choose one of the following fields of study.

Anatomical Index

The first time during each of your turns that you damage the target, it takes additional psychic damage equal to your proficiency bonus.

Defensive Index

The first attack roll made against the target by you or an ally during each round ignores half cover.

If the attack would already ignore half cover, the attacker instead adds one roll of your Archive Die to the attack roll.

Behavioral Index

The first time during each round that the target makes an attack roll, you can subtract one roll of your Archive Die from that attack.

No action is required.

Esoteric Index

The first time during each round that the target makes a saving throw against one of your Warlock spells, you can subtract one roll of your Archive Die from the saving throw.

You must decide before the outcome is declared.

Your Archive Die is a d4. It becomes a d6 at 10th level and a d8 at 14th level.

A creature is aware that you are supernaturally studying it but does not automatically know which Index you selected.

You can use Index the Subject a number of times equal to your proficiency bonus, regaining all expended uses when you finish a long rest.

Action Type: Bonus action
Uses: Proficiency bonus per long rest
Range: 60 feet
Duration: 1 minute
Scaling: Archive Die improves at 10th and 14th level

Consult the Catalogue

When you make an Arcana, History, Investigation, Nature, or Religion check, you can consult the Codex and roll your Archive Die, adding the result to the check.

You can use this feature after rolling the d20 but before the Game Master declares whether the check succeeds.

You can use Consult the Catalogue a number of times equal to your Charisma modifier, with a minimum of once. You regain all expended uses when you finish a long rest.

If the check concerns a creature currently affected by Index the Subject, you do not expend a use.

You can benefit from this free use only once for each activation of Index the Subject.

Action Type: No action
Uses: Charisma modifier per long rest; one free use per indexed subject
Duration: Instantaneous
Scaling: Uses your Archive Die

Archival Recall

Your Codex can retrieve fragments of expertise, precedent, and magical theory from the Infinite Archive.

When you or a creature you can see within 60 feet makes an ability check or saving throw, you can use your reaction to roll your Archive Die and add it to the result.

You can use this reaction after the d20 is rolled but before the outcome is declared.

You can use Archival Recall a number of times equal to your proficiency bonus, regaining all expended uses when you finish a long rest.

When you use Archival Recall, choose one of the following annotations.

Relevant Precedent

The creature also gains proficiency in the associated ability check for that roll. If it was already proficient, this annotation has no additional effect.

Corrective Citation

If the roll is a saving throw against a spell or magical effect and still fails, the creature gains resistance to any damage dealt by that effect.

The resistance applies only to damage caused immediately by the failed saving throw.

Borrowed Method

If the roll is an ability check and succeeds, the creature retains the borrowed technique for 10 minutes. During that time, it can add half your proficiency bonus, rounded down, to one additional check using the same skill or tool.

The benefit then ends.

Action Type: Reaction
Uses: Proficiency bonus per long rest
Range: 60 feet
Duration: Instantaneous or 10 minutes
Scaling: Uses your Archive Die

Expose the Omission

You can identify the gap in a creature’s defenses and briefly make that weakness apparent to your allies.

When a creature affected by Index the Subject:

• Misses with an attack.
• Fails a saving throw.
• Takes damage from one of your Warlock spells.
• Has a spell interrupted or dispelled.

You can use your reaction to expose an omission in its defenses.

Choose one of the following effects.

Missing Guard

The next attack roll made against the creature before the beginning of your next turn has advantage.

If the attack hits, it deals additional damage equal to one roll of your Archive Die.

Faulty Formula

The creature has disadvantage on the next Constitution saving throw it makes to maintain concentration before the beginning of your next turn.

Incorrect Assumption

The creature cannot take reactions until the beginning of your next turn.

Unstable Defense

Choose acid, cold, fire, lightning, necrotic, psychic, radiant, or thunder.

The next time the creature takes the chosen damage type before the beginning of your next turn, it takes additional damage equal to your Warlock level.

This feature does not remove resistance or immunity.

You can use Expose the Omission a number of times equal to your Charisma modifier, with a minimum of once. You regain all expended uses when you finish a long rest.

Action Type: Reaction
Uses: Charisma modifier per long rest
Range: Indexed creature
Duration: Until the beginning of your next turn
Scaling: Uses Archive Die or Warlock level

Warden of the Archive

The Librarian entrusts you with the defenses used to protect dangerous knowledge.

You gain resistance to psychic damage.

Your thoughts cannot be read through telepathy or magic unless you permit it.

Magic cannot force you to reveal information you deliberately intend to protect. This does not allow you to speak a lie within Zone of Truth or similar magic; instead, you may remain silent even if another magical effect would ordinarily compel an answer.

You have advantage on saving throws against effects that would:

• Alter your memories.
• Remove knowledge from your mind.
• Possess you.
• Cause you to forget a language, proficiency, or identity.
• Force you to reveal a secret.

Sealed Memory

As an action, you can place one memory, fact, name, image, route, or piece of information you know into a sealed section of your Codex.

While sealed:

• You still know that the information exists.
• You cannot consciously recall its details.
• Other creatures cannot extract it from your mind.
• Magic that reads your thoughts perceives only a closed page or locked door.
• You cannot willingly communicate the sealed information.

You may unseal the information as a bonus action.

You can maintain a number of sealed memories equal to your Charisma modifier.

Sealing a new memory beyond this limit causes one existing sealed memory of your choice to return.

Custodian’s Interdiction

When a creature you can see within 60 feet attempts to read thoughts, alter memories, possess another creature, or magically obtain protected information, you can use your reaction to force it to make an Intelligence saving throw against your Warlock spell save DC.

On a failed save:

• The triggering effect fails against one target of your choice.
• The creature takes psychic damage equal to twice your Warlock level.
• It cannot attempt to read or alter that target’s mind again until the beginning of its next turn.

On a successful save, the target has advantage on any saving throw caused by the triggering effect.

You can use Custodian’s Interdiction a number of times equal to your proficiency bonus, regaining all expended uses when you finish a long rest.

Action Type: Passive; action to seal a memory; reaction
Uses: Interdiction—proficiency bonus per long rest
Range: 60 feet
Duration: Varies
Scaling: Psychic damage equals twice Warlock level

Ethereal Archivist

You can manifest a spectral custodian from the Infinite Archive.

As a bonus action, summon the Archivist in an unoccupied space you can see within 30 feet.

The Archivist is a Medium spectral entity. It does not count as a creature, cannot be attacked or damaged, and can share a space with other creatures.

It lasts for 1 minute, until you are incapacitated, or until you dismiss it as a bonus action.

The Archivist has a flying speed of 30 feet and can hover. You can move it up to its speed as a bonus action.

While the Archivist is present, it produces a 10-foot aura with the following effects.

Quiet Reading Room

Enemies in the aura have disadvantage on Constitution saving throws made to maintain concentration.

Protective Stacks

You and allies of your choice in the aura have advantage on Intelligence saving throws and on saving throws against illusions.

Reference Desk

Once during each of your turns, you can cast a Warlock cantrip as though you occupied the Archivist’s space.

Restricted Access

When an enemy enters the aura for the first time on a turn or starts its turn there, you can reduce its speed by 10 feet until the beginning of its next turn.

You can summon the Ethereal Archivist once per long rest.

You can regain its use by expending one Pact Magic spell slot as a bonus action. Once you recover the feature this way, you cannot do so again until you finish a long rest.

Action Type: Bonus action
Uses: Once per long rest; one recovery through Pact Magic
Range: 30 feet
Duration: 1 minute
Scaling: Uses your spellcasting and Warlock cantrips